In a conventional computer network (e.g., a local area network or wide area network), computers communicate over a network infrastructure made up of interconnected nodes, such as routers and/or switches, connected by communication links such as optical fiber, copper cable, and wireless links. Often, the topology is such that each node connects to multiple neighboring nodes (e.g., as in a mesh configuration).
Typically, data propagates through such a network in discrete units referred herein as “packets” (meaning any fixed- or variable-sized discrete unit of data, including frames, cells, segments, or packets). For each received packet, a node examines the contents of the packet (e.g., a destination address in the packet header) and determines which neighboring node to forward the packet to. Often, a node makes this determination by performing a table lookup. The neighboring node performs a similar determination until the packet eventually propagates from node to node through the network to its destination.
When a node (or a component in the node) fails, the node may no longer be operative to forward packets. Such a failure may result in serious disruption to the performance of the network. Even after the failure is repaired, there may be a delay before the node becomes fully operational, resulting in continued disruption to the network. In routers, for example, the operation of certain components may depend upon state information, which is maintained in the router according to the contents of previously forwarded packets. Accordingly, once the failure in the router is finally repaired, it may take some amount of time for the router to generate sufficient state information for it to function properly.
Thus, there is a need for an invention that more adequately addresses such problems which may occur in the network.